Machine and method for sealing vitreous vessels



April 16, 1940. D N 2,197,527

MACHINE AND METHODFOR SEALING VITREOUS VESSELS Filed June 8, 1958 lNVENTOR ATTO R N EY Patented Apr. 16, 1940 PATENT OFFICE momma AND METHOD FOR SEALING VITREOUS VESSELS Barry D. Madden, South Orange, N. J., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application June s, 1938, Serial No. 212,484

Claims.

The principal object of my invention, generally considered, is the tipping-01f of the exhaust tubes of incandescent electric lamps, and other devices having vitreous envelopes, which have been filled with gas at a pressure higher than atmospheric.

Another object of my invention is the provision of a method and machine for tipping ofl exhaust tubes while enclosed in a space containing gasat a pressure higher than atmospheric.

A further object of my invention is the provision of a method and machine for sealing vitreous vessels or lamps having exhaust tubes, in which the device is first positioned with its tube in an exhaust rubber, a pressure chamber being provided for enclosing the portion of said tube to be'tipped oil, with means for applying pressure in said tipping-off chamber, a suction cup then engaging the top of the device, the exhaust tube being heated in said chamber by means of oxyhydrogen or other flames, whereupon the engaging cup is rotated and raised, twisting and pulling out the exhaust tube to effect the sealing operation.

' tipping-off of the exhaust tubes of vitreous vessels, such as incandescent electric lamps, by -means of a sharp oxyhydrogen flame, while said tubes are being twisted.

Other objects and advantages of the invention, relating to the particular arrangement and construction. of the various parts, will become apparent as the description proceeds.

Referring to the drawing:

Fig. 1 is a view, partly in side elevation and partly in vertical section on the line I--I of Fig. 4, in the direction of the arrows, of airagmentary portion of apparatus embodying-my invention, an associated lamp being shown in side elevation.

Fig. 2 is 'a view corresponding generally to Fig. 1 except that more of the apparatus is shown in elevation, as most of the section is on the line 11-11 of Fig. 4, in the direction of-the arrows, the lamp exhaust tube in this position having been slightly twisted and the lamp raised for the purpose of effecting a'tipplng-ofi operation.

Fig. 3 is a view corresponding generally to Fig. 2, but showing the position of the lamp when the tipping an operation has been completed and the exhaust tube severed.

A still further object of my invention is the Fig. 4 is a plan view of the apparatus, on the line IV-IV of Fig. 1', in the direction of the arrows.

Fig. 5 is an elevational view of a lamp, as shown in Figs, 1, 2, and 3, after having been removed from the machine.

In the Gustin application, Serial No. filed May 22, 1937, and owned by the assignee of the present application, there is disclosed a method and machine for sealing vitreous vessels, in which a portion of the exhaust tube of each vessel is enclosed in a pressure chamber and heated until it contracts and effects a seal. In

accordance with the present invention, I propose to use a similar pressure chamber, but, in addition, effect the sealing operation while the vitreous vessel is simultaneously twisted and raised, thereby expediting the formation of the seal as well as making for greater certainty in its production. V

Incandescent electric lamps, as conventionally manufactured, each include a glass bulb having a neck portion into which a so-called stem is sealed. The stemincludes a flare tube, one end of which is flanged and sealed to the bulb neck, and the other terminates in a flattened portion or press through which conductive lead wires are sealed and upon which a filament is mounted. Within the. flare tube and extending downwardly from the press are the lead wires, and the exhaust tube leads from an orifice in the flare tube or press for thepurpose of exhausting the bulb or filling it with gas at a desired pressure.

When manufacturing lamps of the vacuum type it has been customary to insert the exhaust tube of each in a port leading to a vacuum pump, and after the air or gas has been exhausted from the bulb of the lamp, said tube is heated until the wall thereof collapses, whereupon the lamp becomes sealed and may be removed in a wellknown manner by a pullingor stretching operation.

When, however, such a lamp, or other vitreous vessel, is filled with a gas at a pressure higher than atmospheric, the exhaust tube will not collapse upon being heated, but rather tends to expand or blow out, due to the internal pressure.

The method which I propose to employ for sealing overcomes this tendency to" blow out by performing the tipping-off operation while surrounded by gas under higher than normal atmospheric pressure, or corresponding with the pressure of the gas in the lamp bulb and exhaust tube therefrom, while at the same time twisting and pulling out said exhaust tube.

In the drawing of a preferred or selected embodiment of my invention, an incandescent electric lamp is shown with a bulb having an exhaust tube l2, inserted in an apertured exhaust rubber |3 of a head l4, only fragmentary portions of which are illustrated. The head is carto a fitting l7, and adapted to press a washer l8 through ball bearings l9. The cap may be rotated at the proper time, as by means of a laterally extending arm 20, to either press the rubber |3 about the exhaust tube i2, or release the pressure thereon to facilitate insertion therein or withdrawal therefrom of such an exhaust tube.

Assuming that a lamp has been placed in the machine so that the exhaust tube I2 is clamped tightly by pressure being applied to the exhaust rubber l3, and the lamp rotated through the stages wherein it was exhausted to the proper degree, the desired inert gas is then admitted to the bulb through the exhaust tube 2 from the inert gas line, not shown, as will be clear from a consideration of Fig. 1. Before admitting gas, however, the vacuum line is cut oil from the lamp in any desired manner, as by means of pressure on a rubber tube connection, as disclosed in the .Gustin application previously referred to.

The bulb I, after being filled with inert gas to the desired pressure, and possibly passing through fires in which the exhaust tube 2 is initially heated immediately beneath the lower part of the stem of the lamp, finally reaches the position illustrated in Figs. '1 and 4, where the tube |2 passes between and separates the bafile plates or spoons 2| and 22, as by moving from the left to take the position represented in Fig. 4, where it is received in portions of the plates 2| and 22, and parts depending therefrom which are notched to provide circular apertures 23 and 24, in which the tube snugly fits when the apparatus is closed.

The bafile plates 2| and 22 carry mechanism, shown more in detail in the Gustin application previously referred to, which will now be briefly described, for performing a tipping-off operation on the exhaust tube l2, while the portion of said tube being tipped off is subjected to a pressure higher than atmospheric. Secured to the lower surfaces of the baiiie plates 2| and 22 are burner shield sections 25 and 26. These sections have their upper edges flanged, as indicated at 21, and secured to the lower surfaces of the baflie plates 2| and 22, respectively, by any desired means, as for example, welding or brazing.

The baflie plates 2| and 22 are pivotally mounted on a fulcrum screw 28 and, together with their supported shields 25 and 26, are normally held in closed position about the exhaust tube |2 by means of a spring 29, operating on extensions 3| and 32, from said baiile plates 22 and 2|, respectively,so that after the exhaust tube l2 has separated the baffle plates slightly from the position shown in Fig. 4, while moving to the right, as viewed in said figure it finally reaches the normal position illustrated in Figs. 1 and 2, whereupon the baffle plates and associated burner shields are closed therearound, forming a substantially air-tight chamber encasing the. portion of said exhaust tube immediately below the bulb II.

In order to effect a heating and sealing operation in the chamber so formed, the baflle plates 2| and 22 are connected to a gas outlet block designated by the reference character 34. Said block closes the back or righthand side of the chamber 33 formed by the burner shield portions below the baffle plates, as viewed in Figs. 1 and 2, for example. Connected to the gas outlet block 34 is a pipe 35, which may supply the desired air pressure to the chamber, through the port 36.

The front or inner face of the block 34 has a threaded portion 31 receiving a screw 38 which carries the burner 39. Said burner is generally U-shaped in plan, as shown most clearly in Fig. 4, and provided with ports 4| and 42 for a suitable mixture of hydrogen and oxygen, for example, or a suitable mixture of other combustible gas and oxygen, air, or a mixture thereof. A plurality of burner orifices 43 extend from the port 4|, and 44, from the port 42, which orifices are very fine so that the oxyhydrogen or other fiame produced therebeyond, will not backfire and is very fine and sharp.

In order to provide for feeding the gases mentioned through the ports 4| and 42, a gas inlet block 45 is secured to the upper portion of the said outlet block 34. The block 45 has downwardly extending ports 46 and 41, with lower openings registering with the upper ends of ports 4| and 42, respectively, in the outlet block 34, so as to provide for the transmission of gases from the manifold nipples 48 and 49, which lead from the gas mixer, not shown.

The rear or righthand portion of the gas inlet block 45, as viewed in Fig. 4, has arms 5| and 52 straddling the pivot head 53,,in order to pivotally support it and associated parts thereon, as by means of pivot screws54 and 55, which are adapted to be locked in adjusted positions by means of nuts 56 and 51. The baiiies, shields, and associated parts are normally resiliently held in their uppermost or chamber-closing position by means of a spoon spring 58, the rear portion of which is secured to the pivot head 53, as by means of a nut 54' threaded on the fulcrum screw 28.

In order to allow for pivotal motion of the baffles 2| and 22 about their pivot pin or fulcrum screw 28 with respect to the gas outlet block 34, and at the same time allow movement thereof, with respect to the connected inlet and outlet blocks and burner 39, about their horizontal pivot screws 54 and 55, so that the baflies 2| and'22 and the burner shield sections 25 and 26 may be firmly pressed into tight engagement with the adjacent face of the outlet block 34, the front or baflie and shield engaging surface of the gas outlet block 34 is made spherical about a center corresponding with the point of intersection between the vertical axis, about which the baffles 2| and 22 pivot, and the horizontal axis about which they are pivoted to the gas inlet, outlet, and burner members. This surface is designated by the reference character 53 and the rear upright edges 6| and 62 of the burner shield sections 25 and 26, respectively, are made vG3 and 64. Likewise the baffles 2| and 22 have their corresponding edges formed circular in outline where they are engaged by the gas outlet block 34, as designated by the reference characters 65 and 66.

' It will therefore be seen that the bailles 2| and 22 are free to open and close, while at the same time they are free to pivot about the horizontal axis of the pivot screws 54 and 55, with respect to the gas inlet and outlet blocks, to release. the gas pressure if it becomes excessive, while allowing the exhaust tube |2 to move horizontally therebetween, said baflles and associated parts being normally pressed firmly into engagement with the curved face 59 of the outlet block 34 to form a substantially air-tight chamber in which the tipping-oft operation is performed. r

In order'to'limit upward swinging movement of the bafflesand associated parts with respect to the inlet, outlet, and burner sections 45, 34, and

39, I provide a set screw 61 passing through the gas inlet block 45, and with its lower end normally engaging, or adapted to engage, a flange 68 of the pivot head 53 engaged by the baflles 2| and 22. Said flange 68 has a stud 69 depending therefrom as a locating pin between the baflles 2| and 22. The set screw 61 may be locked in adjusted position by means of a nut In order to effect the twisting and raisingpf the lamp after the exhaust tube thereof has been means of a flexible tube 8|.

Rotation of the spindle 18 and cup 19 is effected on corresponding movement of the actuating arm ll through rod 82 pivotally connected thereto as indicated at 83, by a stud 84 outstanding from the spindle I8 and reciprocable in a corresponding slot 85 in the hub Hi. A coil spring 86 holds the cup I9 and its spindle I8 normally in lowermost position, but allows movement thereof, to

the necessary extent, with respect to the hub 16, upon counterclockwise rotation of said hub, as

viewed in Fig. 4, and engagement thereof with the bulb I, so that undue strain on the bulbdoes not occur. Upon subsequent clockwise rotation of the hub 16, by corresponding movement of the haust tube I 2, after the same has been heated y to a softening temperature, and effecting the desired seal therein.

From the foregoing disclosure it will be seen that I have provided means whereby the lamp bulb i I, or other hollow vessel, may be exhausted, filled with an inert gas, and finally moved to a position where that portion of its exhaust tube l2, immediately below the bulb neck, is enclosed in the chamber 33, formed by the baflle plates 2| and 22, above, the burner shields 25 and 24 to the sidesand front, and the gas outlet block '34 to the rear.

While so enclosed, oxyhydrogen flames or other heating means are positioned to create a heat zone about the tube i2 at a point designated by the reference character 81, to rapidly seal andcut off the tube, while air pressure supplied by pipe 35 prevents expansion of the exhaust tube, while allowing it to contract naturally in accordance with the surface tension of the glass to seavoiding an undesired accumulationof glass atthe point of tipping-off. During the sealing or tipping-off operation, the lead wires 88 are, of

course, bent to lie above the baiiie plates 2| and 22, protected from damage by excessive heat.

The ba'flles 2| and 22 are pivotally mounted about the pin 28, so that they may move away from and toward one another to allow for the reception and release of the exhaust tubes of lamps associated therewith, and pivotally mounted about a=horizontal axis with respect to the gas outlet-block and associated parts, while .spring pressed upwardly, thereby maintaining the chamber 33 closed to as great an extent as possible, and avoiding an unnecessary escape of compressed air'and gas, even when the bailles are open for the reception of an exhaust tube. The bulb I, after being tipped off, may be removed by hand or by the usual automatic means.

Although a preferred embodiment of my invention has been shown, it will be understood that modifications-may be made within the spirit and scope of the appended claims.

I claim:

l. 'I'hemethod of sealing a vitreous vessel, gasfllled to a super-atmospheric pressure, and having an exhaust tube, comprising enclosing a portion of said tube in a chamber, creating a pressure above atmospheric in said chamber, heating said tube, and twisting the same to cause it.to collapse for tipping-off purposes.

2. The method of sealing a vitreous vessel hav-' ing a tubular extension after said vessel is filled with a gas above atmospheric pressure, comprisingenclosing a portion of said extension in a chamber, creating a pressure above atmospheric in said chamber, heating said tube in said chamber, and twisting the same to effect tipping-off thereof. I

3. The method of tipping-off an exhaust tube from a vessel containing a gas at a pressure above.

atmospheric, comprising enclosing a portion of said tube in a chamber containing gas at a pressure corresponding with that of the pressure in said vessel, heating said exhaust tube in said chamber to its softening point, and twisting to effect a seal.

4. The method of sealing-off lamps, gas-filled to a super-atmospheric pressure, and having exhaust tubes, comprising applying heat to soften said tubes, andi twisting under super-atmospheric pressure to eflect a tipping-off thereof.

. ,5. The method of sealing-off a lamp gas-filled above atmospheric pressure and having an exhaust tube, comprising positioning only a portion of said tube in an enclosed space, introducing into said space a gas above atmospheric pressure like that of the fill gas, heating said portion to soften the wall thereof and twisting and elongating said tube to effect sealing thereof.

6. The method of tipping-off lamps gas-filled above atmospheric pressure, comprising enclosing only portions of the exhaust tubes thereof in a closed chamber, introducing gas into said chamber at a pressure above atmospheric like that of the fill gas. directing oxyhydrogen flames on said enclosed portions, and twisting to effect a sealing operation.

'7. The method of sealing a. vitreous vessel having an exhaust tube extending therefrom comprising positioning said tube in an exhaust rubber for evacuation and gas filling, moving said vessel so that a portion of said tube is enclosed in a pressure chamber, applying pressure in said chamber to balance the gas filling in said vessel, softening the tube in said chamber by the application of heat, and finally rotating and raising said vessel to twist, pull out, and seal the exhaust tube thereof.

8. The method of sealing a vitreous vessel gasfilled above atmospheric pressure having an exhaust tube, comprising enclosing a portion of said tube in a chamber, maintaining a pressure above atmospheric in said chamber, heating said tube, and twisting the same to cause it to collapse for tipping-01f purposes.

9. The method of sealing a vitreous vessel having an exhaust tube extending therefrom comprising positioning said tube in an exhaust rubber for evacuation and gas filling, moving said vessel so that a portion of said tube is enclosed in a chamber, softening the tube in said chamber by the application of heat, and finally rotating and raising said vessel, to twist, pull out, and seal the exhaust tube thereof.

10. A machine for tipping off exhaust tubes of vessels, comprising a chamber enclosing a tipping-off burner, means for accomplishing the insertion and removal of an exhaust tube of such a vessel with respect to said chamber, and means for twisting said vessel while said exhaust tube is softened by heat of said burner, to facilitate sealing thereof. I

11. A machine for tipping off exhaust tubes of vessels containing gas at a pressure higher than atmospheric, comprising a chamber enclosing, a tipping-off burner, means for accomplishing only the insertion and removal of an exhaust tube of 'such a vessel with respect to said chamber, and

means for twisting said vessel while said exhaust tube is softened by heat, to facilitate sealing thereof.

12. A machine for tipping off exhaust tubes of vessels comprising a tipping-ofi' burner, means for accomplishing the insertion and removal of an exhaust tube of a vessel with respect to said burner, and means for twisting and raising said vessel, after softening of the exhaust tube by said burner, to facilitate the tipping-off operation.

13. A machine for tipping 01f exhaust tubes of vessels containing gas at a pressure higher than atmospheric, comprising a chamber enclosing a tipping-off burner, means for introducing compressed air into said chamber, means for inserting and removing an exhaust tube of a vessel with, respect to said chamber, and means for twisting and raising said vessel, after softening the exhaust tube, to facilitate the tipping-off operation.

14. A machine for tipping-off the exhaust tubes of incandescent electric lamps, comprising a chamber defined by pivotally mounted walls which are normally pressed together, but movable away irom one another to admit exhaust v tubes, a tipping-01f burner normally enclosed by said walls, means for introducing gas at higher than atmospheric pressure into the space defined by said walls, and means for gripping a lamp, and

raising and twisting the same after softening its exhaust tube, to effect a tipping-off operation.

15. A machine for tipping-off exhaust tubes of incandescent electric lamps comprising a gas inlet block, a gas outlet block depending therefrom, a pair of baflles pivotally movable about a normally vertical axis, complementary burner shield portions carried by said bafiles, said baffles and shield portion: being pivotally mounted to rotate with respect to said blocks about a normally horizontal axis, said baffles, shields and outlet block normally engaging surfaces of one another to define a chamber, a burner block secured to said outlet block and normally enclosed in said chamber, the surface of said outlet block engaged by said baflies and shields being spherical with its center at the point of intersection of said vertical and horizontal axes, the engaged edges of said baflies and shields being correspondingly circular, resilient means for pressing said circular edges into engagement with said spherical surface to provide a substantially air-tight chamber enclosing said burner, a vertically reciprocal suction cup disposed above said chamber, means connecting said cup to a vacuum line in order to cause it to adhere to an associated lamp, and means associated with said cup for twisting and raising it to effect corresponding motion of the associated lamp to facilitate the sealing operation.

HARRY D. MADDEN. 

